Several as I used to be in a job which meant coming into contact with famous people every day.
Ones that stand out.
Victoria Beckham looking miserable as sin and troweling on layer after layer of thick slap to cover her acne on a flight to Leeds or Teeside or somewhere. (Back in the '90s).
John Leslie shoving his hand up my skirt and whispering forcefully in my ear that I was a dirty bitch and no mistake.
Snogging, proper snogging George Clooney & Mark Whalberg. On the same flight. 
Carol Smillie always holding up the last flight back from Edinburgh and taking ages to board and stow her stuff like she was Queen Bee. She has a mouth on her.
Joan Collins charm personified. Lovely lady.
Richard E Grant hiding behind a newspaper and refusing to look at anyone because he was sat in economy. He only drank tap water all flight.
Gary Linekar another misery guts who didn't want to sit next to his first wife and who was damn rude to the pilot on a flight deck visit, not even feigning interest when the pilot being from Leicester, told Gaz that his aunt used to babysit him,
Jerry Hall being so gracious when I had to inform her that the ground handlers had lost her baby's buggy on the tarmac in Nice and who despite having a nanny was completely hands on with all her children and stood there on the bus holding a baby with all the other plebs, demanding no special treatment and having no tantrums for lost buggy.
Getting George Galloway kicked off a flight for threatening me with violence because he wouldn't accept his ticket read economy.
I could be here all day...